This invention relates to physical medicine treatment and more specifically to RF diathermy and faradic muscle stimulation treatment for wound healing and treatment of various conditions by application of heat and/or muscle stimulation.
Applying heat to a wound has been recognized as a viable treatment for wound healing. Electrical-pulse neuromuscular stimulation has been used to aid in wound healing. In each case, it is believed that blood flow and, consequently O2 flow to wound tissue is increased. Increased blood flow and thus O2 flow to the wound tissue is believed to be of substantial aid in wound healing.
Resonant RF coil systems and specifically shortwave diathermy, deep-heating modality (see, Lehman, supra) can be used to provide warmth to the extremities. U.S. Pat. No. 4,527,550 to Ruggera describes a coil designed for use under full wave operation at coil wire-length resonance, designed to provide maximum muscle healing. The Ruggera coil system was operated at whatever frequency was determined to be the xe2x80x9cresonantxe2x80x9d frequency for the body-limb/coil combination. It would thus have to be operated within an electromagnetically shielded room in most instances in order to meet FCC noise requirements.
U.S. Pat. No. 4,685,462 to Olsen describes an apparatus for rewarming hypothermia victims. U.S. Pat. No. 5,160,828 to Olsen discloses a device for warming the extremities of a subject, such as a deep-sea diver, in a cold wet environment, so that the subject can perform agile tasks in such an environment. The Olsen coil systems were designed to be tuned to specific xe2x80x9cIndustrial-Scientific-Medicalxe2x80x9d (ISM) frequencies and, therefore, could be operated in free-space, and without shielding, without environmental interference.
The use of electrical-pulsed neuromuscular stimulation has been suggested as treatment for peripheral vascular insufficiency. See Lehman, J. F., Therapeutic Heat and Cooling, Rehabilitation Medicine Library (1990, 4th edition), p. 458; cf. U.S. Pat. No. 4,368,410 to Hance et al. (ultrasound); U.S. Pat. No. 4,791,915 to Barsotti (ultrasound). Such neuromuscular stimulation can increase the flow rates of blood and lymphatic fluid by both mechanical and electrical means. The physical contractions mechanically xe2x80x9csqueezexe2x80x9d the muscles and blood vessels, and the application of electrical current pulses helps maintain the tonicity of the vessels. Although neuromuscular stimulation alone produces some beneficial effects, its effectiveness is limited.
Previously, a convenient device and method for shortwave diathermy and/or neuromuscular stimulation had not been devised to treat slow or non-healing wounds due to vascular insufficiency, diabetic peripheral neuropathy, microangiography, microvascular disease, or compression neuropathies such as Carpal Tunnel Syndrome. Furthermore, most previous and related treatment were designed for use by or under the immediate supervision of a health-care practitioner.
The present invention pertains to a device and method for wound treatment and treatment of various other conditions such as diabetic peripheral neuropathy, microangiography, osteoarthritis, microvascular disease, and/or compression neuropathies. A resonant diathermy coil system for deep heating is provided in combination with a muscle stimulator. RF heating of tissue can be accomplished in conjunction with muscle stimulation. Alternatively, either therapy, RF heating or muscle stimulation can be applied independently. The device of the present invention includes specially adapted components to accomplish the therapies as described in more detail below.
In one embodiment of the present invention, an RF diathermic coil assembly includes a primary coil. The primary coil includes a plurality of windings that are ostensibly helical and connected to a power source. The assembly also includes a secondary coil including a plurality of windings disposed proximate the primary coil. The purpose of the two coils is to provide a convenient impedance-matching method between the cable-connected power source (typically 50 ohms) and the resonant secondary coil with typical end-to-end impedance of hundreds of ohms. Therefore, the secondary coil preferably includes more windings than the primary coil. A means for tuning the body-part-plus-coil system to resonance is provided.
A means for tuning is necessary because various body parts inside a given coil system to be diathermally heated present different dielectric (capacitive) parameters and, as such, would cause the resulting resonant frequency to vary slightly. Adjusting the system to resonance can be accomplished by changing either the inductance of the coils or the capacitance of the system, most of which capacitance consists of body tissues inside the coils. Small changes in coil inductance can be made either by changing the helical length of the conductor or by changing other physical coil characteristics such as diameter or pitch. Small changes in the capacitance of the system are easily made by connecting a variable capacitor with sufficient voltage rating within the range of approximately 4 to 26 picofarads in parallel with the secondary winding. The present invention makes use of the variable capacitor. In some applications, a balun coil is added, close to the diathermic coils, in series with the coaxial cable that connects to the RF energy source. The purpose of the balun coil is to make the distribution of RF tissue warming more uniform, symmetrical, and not affected by nearby wires and/or metallic objects that share a common electrical ground with the RF energy source.
In one embodiment, the coil can be incorporated into an elastically deformable patient conforming garment. The coils are secured to the garment. The conductive portion of the coils has a woven construction such that the coils can be deformed as the garment elastically deforms. A woven RF shield can be incorporated into the garment.
An elastic wire assembly can be used to form the coils. Elastic wire assembly can include a non-conductive elastic core, a woven conductor secured to the core and a non-conductive elastic sheath over the woven conductor. The elastic core can include a plurality of polymer strands which can be deformed elastically. The non-conductive elastic sheath can include a woven fabric. The device as described herein can incorporate or be used in conjunction with a muscle stimulator for treatment of various conditions and wound healing. When used for wound healing the patient wearable garment with coil is connected to a patient. The coil is activated to heat a patient""s body part to create increased blood circulation therein. Electrodes of the muscle stimulator are placed proximate to the muscles at the wounded body part. The muscles are then stimulated to increase blood circulation therein. Muscle stimulation is preferably performed while the RF coil is turned off.